We know different material has different density and acoustic impedance. A particular value needs to be specified to get the actual deposition thickness of a particular material through thickness monitor. I shall be highly obliged if anyone can provide me the value of acoustic impedance that should be set for In2O3 and Er2O3 in electron beam evaporation.
What kind of thickness monitor do you use? If you are using a quartz crystal balance (Inficon for example) you normally don't need the acoustic impendence explicitly for measuring as the frequency change of the crystal is only determined by the added mass.
Nevertheless there is correction factor to match the acoustic properties of the deposited material to the crystal. According to the Inficon XTC/2/3 manual this factor can be kept at 1 for most processes. The error will be neglectable if the crystal lifetime is sufficient high and you are not evaporating a lot of different layers on a single sample.
Also see this question: https://www.researchgate.net/post/What_values_of_parameters_acoustic_impedance_density_thickness_should_I_use_in_the_thermal_evaporation_technique_to_deposit_silver_nanoparticles
Anyway the manual of your monitor should specify how you can measure the Z-factor without knowing the acoustic impedence.
We use quartz crystal based thickness monitor with frequency of 6 MHz. But we have to fix density and acoustic impedance to get an exact value of thickness. However, in our thickness monitor we don't have any option to set the Z factor, which I hope something other than acoustics impedance. Is it true that if we are unable to give an exact value of a.i., then also we will get the value of thickness close to the value shown by thickness monitor?
For my monitor the Z-value is defined by acoustic impendence of the crystal divided by acoustic impedence of the evaporated material.
Do you have any method to test the thickness after evaporation? You could simply evaporate some material with a guessed acoustic impedence setting. If you make several samples with different thickness, a totallyincorrect impedence value should be noticable as a non-linear deviation from your tooling value.
This way you could tweak the impedence setting by fitting the target thickness to the measured one. But still, I would first try to simply evaporate some material without worring about the impedence value at all.
I agree with you that "I would first try to simply evaporate some material without worrying about the impedance value at all". But, if I know the value then I can set it to get the desired thickness of the film more closely. By the way, I'm using quartz crystal with ACI 8.83. Can you supply the Z factor value of In2O3, so that I can calculate ACI of it?
Unfortunatly in all my tables In2O3 is listed with an unknown Z factor (==1).
If you do not know the acoustic impedance set it to 1. It generally only affects thick layers
Inficon XTM2 manual has a good list of Z ratios in Appendix A but has Er2O3, and In2O3 as 1 which may be default as unknown
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